Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds
Basal conditions directly control the glacier sliding rate and the dynamic discharge of ice. Recent glacier destabilization events indicate that some marine-terminating glaciers quickly respond to lubricated beds with increased flow speed, but the underlying physics, especially how this vulnerabilit...
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ftcopernicus:oai:publications.copernicus.org:tc98920 2023-05-15T15:09:00+02:00 Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds Zheng, Whyjay 2022-04-21 application/pdf https://doi.org/10.5194/tc-16-1431-2022 https://tc.copernicus.org/articles/16/1431/2022/ eng eng doi:10.5194/tc-16-1431-2022 https://tc.copernicus.org/articles/16/1431/2022/ eISSN: 1994-0424 Text 2022 ftcopernicus https://doi.org/10.5194/tc-16-1431-2022 2022-04-25T16:22:30Z Basal conditions directly control the glacier sliding rate and the dynamic discharge of ice. Recent glacier destabilization events indicate that some marine-terminating glaciers quickly respond to lubricated beds with increased flow speed, but the underlying physics, especially how this vulnerability relates to glacier geometry and flow characteristics, remains unclear. This paper presents a 1D physical framework for glacier dynamic vulnerability assuming sudden basal lubrication as an initial perturbation. In this new model, two quantities determine the scale and the areal extent of the subsequent thinning and acceleration after the bed is lubricated: Péclet number ( Pe ) and the product of glacier speed and thickness gradient (dubbed J 0 in this study). To validate the model, this paper calculates Pe and J 0 using multi-sourced data from 1996 to 1998 for outlet glaciers in the Greenland ice sheet and Austfonna ice cap, Svalbard, and compares the results with the glacier speed change during 1996/1998–2018. Glaciers with lower Pe and J 0 are more likely to accelerate during this 20-year span than those with higher Pe and J 0 , which matches the model prediction. A combined factor of ice thickness, surface slope, and initial flow speed physically determines how much and how fast glaciers respond to lubricated beds in terms of speed, elevation, and terminus change. Text Arctic Austfonna glacier glacier Greenland Ice cap Ice Sheet Svalbard Copernicus Publications: E-Journals Arctic Svalbard Greenland Austfonna ENVELOPE(24.559,24.559,79.835,79.835) The Cryosphere 16 4 1431 1445 |
institution |
Open Polar |
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Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Basal conditions directly control the glacier sliding rate and the dynamic discharge of ice. Recent glacier destabilization events indicate that some marine-terminating glaciers quickly respond to lubricated beds with increased flow speed, but the underlying physics, especially how this vulnerability relates to glacier geometry and flow characteristics, remains unclear. This paper presents a 1D physical framework for glacier dynamic vulnerability assuming sudden basal lubrication as an initial perturbation. In this new model, two quantities determine the scale and the areal extent of the subsequent thinning and acceleration after the bed is lubricated: Péclet number ( Pe ) and the product of glacier speed and thickness gradient (dubbed J 0 in this study). To validate the model, this paper calculates Pe and J 0 using multi-sourced data from 1996 to 1998 for outlet glaciers in the Greenland ice sheet and Austfonna ice cap, Svalbard, and compares the results with the glacier speed change during 1996/1998–2018. Glaciers with lower Pe and J 0 are more likely to accelerate during this 20-year span than those with higher Pe and J 0 , which matches the model prediction. A combined factor of ice thickness, surface slope, and initial flow speed physically determines how much and how fast glaciers respond to lubricated beds in terms of speed, elevation, and terminus change. |
format |
Text |
author |
Zheng, Whyjay |
spellingShingle |
Zheng, Whyjay Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds |
author_facet |
Zheng, Whyjay |
author_sort |
Zheng, Whyjay |
title |
Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds |
title_short |
Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds |
title_full |
Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds |
title_fullStr |
Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds |
title_full_unstemmed |
Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds |
title_sort |
glacier geometry and flow speed determine how arctic marine-terminating glaciers respond to lubricated beds |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-1431-2022 https://tc.copernicus.org/articles/16/1431/2022/ |
long_lat |
ENVELOPE(24.559,24.559,79.835,79.835) |
geographic |
Arctic Svalbard Greenland Austfonna |
geographic_facet |
Arctic Svalbard Greenland Austfonna |
genre |
Arctic Austfonna glacier glacier Greenland Ice cap Ice Sheet Svalbard |
genre_facet |
Arctic Austfonna glacier glacier Greenland Ice cap Ice Sheet Svalbard |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-16-1431-2022 https://tc.copernicus.org/articles/16/1431/2022/ |
op_doi |
https://doi.org/10.5194/tc-16-1431-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
4 |
container_start_page |
1431 |
op_container_end_page |
1445 |
_version_ |
1766340248602673152 |